Fuse construction



March 9,1943. w. o. SCHULTZ v v 2,313,365

- FUSE CONSTRUCTION I Filed March 4, 1939 -2 She'ts-Sheeft 2 Will/7M 0/30 0172 INVENTOR.

ATTORNEY.

Patented Mar. 9, 1943 FUSE CONSTRUCTION William 0. Schultz, South Milwaukee, Wis., as-

signor to Line'Material Company, South Mil- 7 Application March 4,

34 Claims.

This invention relates to fuse constructions.

Objects of this invention are to provide a novel form of fuse, preferably a housed type of expulsion fuse, in which the fuse tube remains stationary after it has blown and the door remains closed, and in which the fuse tube is relieved of potential stress between the contacts after it has blown so that there is no danger of burning the fuse tube or the door even though the fuse tube may be left in an unfused condition for a material length of time.

Further objects are to provide a construction in which an indicator or semaphore is provided and is displayed when the fuse has blown, thereby giving an indication that the fuse hasblown, and to provide means for mechanically withdrawing the fuse -link, such means acting in a direction substantially in line with the fuse tube at the initial portion of its stroke as distinguished from pulling the link around the end of the tube, whereby links of less flexibility may be used and whereby a positive extraction of any remaining portion of the fuse link is provided by mechanical means so that in addition to the expulsion action of the fuse tube there is a mechanical clearing of the fuse tube.

Further objects are to provide a construction in which the fuse link is directly attached to the switch and in which the switch and fuse link extracting means are so arranged that the switch is held in closed position until after the fuse link extracting means has operated and extracted any remaining portion of the fuse link, such fuse link extractin means thereafter engaging the switch means and suddenly opening the switch means due to the momentum acquired by the fuse link extracting means and due to a spring acting on the fuse link extracting means.

Further objects are to provide a novel form of construction in which the refusing may be done in a very simple manner, the construction being such that when the fuse link extracting means is moved back to its initial position during refusing, the switch is automatically projected or rocked so that the switch occupies its initial position and arrives in its initial positon in a wholly automate manner without any thought on the part of the operator.

Further objects are to provide means for further interrupting the circuit in addition to that produced by the fusing of the fuse link, such means coming into operation only after the fuse link has melted and has been expelled or withdrawn from the fuse tube, such additional means operating although the fuse tube remains stationary.

Further objects are to provide a construction in which the mechanical means for withdrawing any remaining portion of the fuse link and the auxiliary means for further interrupting the circuit, in addition to that provided by the melting of the fuse link, are supported from the door, in which the entire assembly of fuse tube, door and mechanical link extracting means and circuit interrupting means may be removed from the housing as a unit for refusing so that the device may be refused while it is completely detached from the remaining portion of the apparatus.

In greater detail, a further object of this invention is to provide an automatically acting switch preferably located adjacent the lower end of the fuse tube and controlled by the fuse link, the semaphore indicating means and the fuse extracting means being also controlled by the fuse link, the switch being held closed until the interruption of the circuit has been effected in the fuse tube and thereafter the switch moving to open position with a quick break and remaining in open position, thus providing an additional point of interruption in the circuit and relieving the fuse tube of potental stresses.

Further objects are to provide a fuse construction in which the automatically operating switch separates any projecting portions of the apparatus or any remaining portion of the fuse link, after the switch has operated, from electrical connection with any live contact of the fuse structure, thereby avoiding hazards. For exam ple, in a construction in which a housing is provided and in which the semaphore or other indicating means is projected outwardly beyond the housing, such semaphore is electrically dead after the operation of the device.

An embodiment of the invention is shown in the accompanying drawings, in which:

Figure 1 is a view, partly in vertical section, showing one form of the device with the parts in operative position.

Figure 2 is a bottom view of the device with a part of the fuse link broken away.

Figure 3 is a fragmentary view of the lower portion of the device with parts in section showing the parts after they have operated.

Referring to the drawings, it will be seen that the device comprises an insulating housing I having an open bottom and a removable door 2 formed of insulating material and provided with trunnions 3 which are removably seated within hook like supporting members 4 carried by the housing. A fuse tube 5 of insulating material is rigidly secured to the door. For example, the fuse tube may be clamped between the members 5 and l, the member I being secured to the door as indicated and if desired, the upper contact 8 of the fuse tube may be provided with a projecting lug 9 secured to an inwardly projecting web If! formed integral with the door 2. A suitable handle I l is provided for the door so that it may be pulled open if desired.

The upper contact 8 of the fuse tube includes a screw cap l2 which may clamp the upper buttonhead l3 of a fuse link. The fuse link may be of any suitable construction and may comprise the fusible section l5 which connects the portion [4 and the flexible leader E6.

The upper terminal member is indicated by the reference character H and may be provided with a pair of spring fingers I? which yieldingly grip the upper contact 8 of the fuse tube, such upper contact being preferably rectangular to provide flattened side portions which are engaged by the spring fingers IT.

The upper terminal is also provided with a spring finger 18 having a downwardly depressed portion l9 adapted to fit over the cap 52 of the fuse tube, the spring finger or contact i8 being upwardly turned at its outer end to provide a cam surface under which the fuse cap is adapted to ride when the device is being closed.

The upper terminal H is provided with a rigid projecting tongue like portion 2%! which is positioned immediately above a lug 2| formed integrally with the upper contact 8 of the fuse tube so as to provide opposed members to carry the force of the recoil of the fuse tube and prevent the upper end of the door from striking the cas- The lower stationary terminal member is indicated at 22 and the major portion of such member constitutes a stationary contact against which the laminated or yielding switch blade 23 is adapted to normally bear. The upper and lower terminals are provided with any suitable means to receive line conductors and these means are preferably set oif to the side of the upper and lower terminal members. Suitable apertures not shown are provided in the housing I through which the line conductors may enter in accordance with the usual practice.

The clamping member 6 is continued downwardly to provide a rigid L-shaped arm having a Vertical portion 24 and 'a horizontal portion 25. The downwardly extending portion 24 may be curved and may fit the fuse tube, as shown in Figure and the horizontal portion 25 may be of channel shape. The horizonal portion terminates in spaced arms which carry a pivot pin 26 and it is to be noted particularly from Figure 2 that the horizontal portion 25 is provided with a pair of outwardly projecting lugs 27 for a purpose that will hereinafter appear.

The switch includes the blade 23 and the body portion 28. This body portion may be hollow so as to reduce its weight and is provided with a rear wall or plate 29 and aforward wall or plate 38. The brush or switch blade 23 may be, as stated, of laminated construction and may be secured by means of screws to the front face of the wall or plate Bil, as shown most clearly in Figure 3. A rectangular clamping washer 3| is positioned on the shank of a screw or bolt 32 and is provided with a tongue 53 that loosely projects below the plate 29 to prevent the washer from turning. The leader H3 of the fuse link is clamped between the plate 29 and. the washer 3|. The body portion 28 of the switch is pivoted on the pivot pin 26.

It is preferable to provide the body portion 28 of the switch with a pair of spaced curved arms 34 which terminate in feet 35. The feet are positioned below the lugs 21 so as to prevent the switch 23 from rocking too far rearwardly when the door is removed from the housing and the device is refused.

A combined fuse link extracting and indicating member, which may be of the form of a semaphore, is provided and comprises the sectorshaped indicating plates 3'! which constitute a semaphore and which are connected by a transverse web 38. The semaphore may be brightly colored, if desired, to increase its visibility when it is projected from the housing.

This combined fuse link extracting and indicating means is also pivoted on the pivot pin 26 and a spring 39 is loosely coiled about the pin and has one end positioned beneath the web of the horizontal supporting arm 25 and the web 38 of the combined fuse link extracting and indicating member so as to urge the fuse link extracting member towards the position shown in Figure 3.

A second spring 46 is also loosely coiled about the pin 26 and bears against the plate 29 of the body portion 28 of the switch and against the web 38 of the fuse link extracting and indicating member, thus tendingto urge the switch in a counterclockwise direction with reference to the fuse link extracting and indicating member. The dotted indication of these spring has been omitted from Figure 1 for the sage of clearnessr If desired, a sleeve, not shgwln may'be placed around the pin 26 to provide a seat for the springs 39 and 40. Whether or not a sleeve is used, the springs 39 and 40 are not allowed to bind upon the pin 26.

The combined fuse link extracting and indicating member is provided with a pair of ears 4! which are adapted to engage the bottom edge of the rectangular washer 31 of the switch so as to limit the relative motion of the fuse link extracting and indicating member and the switch, and particularly to provide means whereby the fuse link extracting and indicating member also opens the switch due to the momentum it acquires when released by the fuse link and also due to the action of its spring 39.

Normally the parts are retained in the position shown in Figures 1 and 2 by means of the fuse link whose leader [6 passes below the web 38 and is clamped between the plate 29 and the washer 3| of the switch. It is preferable to provide a cut-out portion 42 in the bottom of the fuse tube 5, as shown in Figure 2, and to provide a notched tongue 43 formed as an integral portion of the web 38 of the fuse link extracting and indicating member.

If desired, the bottom portion of the fuse tube 5 may be provided with flat portions 44 to thus allow the combined fuse link extracting and indicating member to be made narrower, that is to say, with the plates 31 of the semaphore closer together.

The operation of the apparatus is as follows: When an overload occurs, the fuse link is rul tured and the fuse link extracting and indicating member is released. It i to be noted that a substantial portion of the stroke of the tongue 43 of the fuse link extracting member is approximately directly downwardly from the bottom end urged in a clockwise direction by its spring 39 as soon as released by the fuse link and quickly removes any remaining portion of the fuse link.

In addition to any action due to the blast of gases downwardly out of the fuse tube, it would also tend to remove any remaining portion of the fuse link. However, any remaining portion of the fuse link is'quickly withdrawn from the fuse tube and a quick rupture of the circuit within the fuse tube occurs. The fuse link extracting and indicating means executes a material part of its rocking motion and acquires a considerable momentum before the ears 4| thereof engage the switch through the medium of the rectangular washer 3| forming a portion of the switch structure. This downward motion of the fuse link extracting and indicating means is produced by the action of both the springs 39 and 40. As soon as the ears 4| engage the plate 3|, the switch and combined fuse link and indicating means operate as a single unit and rock about the pivot pin '26 giving a quick opening stroke to the switch and thus interrupting the circuit at an additional point other than that within the tube. The fuse tube, therefore, is relieved of potential stresses and although it may not be refused for a material length of time, nevertheless no deterioration can occur as the circuit between the upper and lower contacts of the fuse tube, the lower contact being the switch structure, is opened by one of the contacts, namely, the switch 23, moving away from the stationary contact 22. Thus there can be no crefiagrrefmzurrent along the fuse tube with consequent destructive or deteriorating effects.

Additionally it is to be noted that the mechanical action of extracting the fuse link is very quick and consequently a quick rupture of the circuit within the fuse tube is first obtained before the switch'opens so that the switch does not burn or pit as no arcing occurs at the switch.

Additionally it is to be noted that the substantially direct downward pull on the fuse link causes the moving parts to acquire considerable velocity and accumulated energy before a change in the direction of pull on the fuse link is pronounced enough to cause appreciable friction between the leader and the side walls of the tube. The result is that even where a stiff leader is used, the momentum of the moving parts would overcome any reasonable friction and stiffness, even though a considerable portion of the leader was not destroyed when the fuse blew.

It is to be noted that after the fuse has blown and the device has operated, that any parts projecting below the bottom of the casing are electrically dead as the lower portion of the aparatus is electrically disconnected from the stationary lower contact, as shown very clearly in Figure 3, and there is, therefore, no hazard due to these projecting parts, such as the semaphore and any remaining portion of the fuse link. This is especially important if the semaphore is made of conducting material, which is the form shown and described, though the invention in its broadest aspect contemplates the making of the semaphore of either conducting or non-conducting material.

The semaphore or indicating portion 31- of the combined fuse link extracting and indicating means projects below the housing I and consequently gives a visual indication that the fuse has blown and needs refusing. If desired, this semaphore may be painted a bright color to further enhance its indicating effect.

It is to be noted particularly that the springs 39 and 40 do not work against each other. Instead the spring 40 holds the brush or switch blade in engagement with the stationary contact until after the fuse link extracting means has extracted any remaining portion of the fuse link,

and on the final portion of the rocking stroke of the fuse link extracting means the ears 4| engage the late or washer 3| and the switch and fuse link extracting means rock as a unit aboutthe pin 26 due to the action of the spring 39 and the momentum acquired by the fuse link extracting and indicating means.

It isto be noted that in refusing, the entire assembly of door, switch and fuse link extracting and indicating means may be readily removed from the housing by lifting the trunnions from the hooks 4 and thereafter it may be refused while removed from the line. Refusing is a simple matter for all that is necessary is to insert the new fuse link, rock the fuse link extracting and indicating means to its initial position, and pass the leader below the web 38, the leader then being clamped between the plates 29 and 3!, thus holding the switch in its extended position and the fuse link extracting and indicating means in its retracted position. After refusing, the assembly is replaced and the door rocked to closed position, thus bringing the switch blade 23 into engagement with the stationary contact 22, as shown in Figure 1. It is to be noted that the spring 40 is not relied upon to hold the switch blade in contact with the stationary contact, but that the feet 35 of the switch rest upon the upper surface of the web 38 of the fuse link extracting and indicating means and thus the switch is mechanically held in position by direct support from the fuse link extracting and indicating means.

It will be seen that an expulsion type fuse construction has been provided in which the circuit is first automatically opened within the fuse tube and thereafter is opened at a second point outside of the fuse tube after the fuse tube has cleared itself, thus relieving the fuse tube of any potential stresses after the fuse link has blown and rior to refusing.

The device is very safe to handle as it may be refused when the active parts are removed from the line. Also if it is desired to open the door and consequently remove the fuse tube from the line manually, this may be readily done by pulling the door open through the medium of the handle or eye H without rupturing the fuse link.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said switch and fuse link being normally connected in series between said contacts, and fuse link extracting means distinct and separate from said switch and biased towards outward motion and having operative engagement with said switch to open said switch when said fuse link extracting means moves outwardly. A

2. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said switch and fuse link being normally connected in Series between said contacts, and fuse link extracting means distinct and separate from said switch and biased towards outward motion and having operative engagement with said switch to open said switch when said fuse link extracting means moves outwardly, said switch when operatively engaged by said fuse link extracting means moving as a unit with said fuse link extracting means.

3. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said switch and fuse link being normally connected in series between said con tacts, fuse link extracting means biased towards outward motion and controlling the opening movement of said switch, a spring between said switch and said fuse link extracting means and tending to produce relative motion between said switch and said fuse link extracting means, and means for limiting said relative motion.

4. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch having a projected and a retracted position, said switch and fuse link being normally in series between said contacts, and fuse link extracting means biased towards outward motion and normally restrained by said fuse link, means for moving said switch to retracted position when said fuse link extracting means moves outwardly, and means for causing operative engagement of said switch by said fuse link extracting means to move said switch to projected position wl'ien said fuse link extracting means is moved inwardly.

5. A fuse, construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said fuse link and said switch be ing normally connected in series between said contacts, indicating means having limited motion independently of said s-witch'and movable to indicating position upon rupture of said fuse link, and means for transmitting motion to said switch from said indicating means to open said switch when said indicating means has moved to indicating position.

6. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said fuse link and said switch being normally connected in series between said contacts, indicating means having limited motion independently of said switch and controlled by said fuse link and biased towards indicating position, and means for transmitting motion to said switch from said indicating means to open said switch when said indicating means has moved to indicating position.

'7. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said fuse link and said switch being normally connected in series between said contacts, indicating means controlled by said fuse link and biased towards indicating position and having limited motion independently of said switch, and means for positively mechanically connecting said indicating means to said switch upon motion of said indicating means to indicating position to open said switch.

8. A fuse construction comprising a pair ofcontacts, a fuse tube, a fuse link within said tube, a switch, said fuse link and said switch being normally connected in series between said contacts, combined fuse link extracting and i n-- dicating means biased towards outward motion and normally restrained by said fuse link and having limited motion independently of said switch, said combined fuse link extracting and indicating means operatively engaging and opening said switch when said combined fuse link extracting and indicating means moves outwardly upon rupture of said fuse link.

9. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said fuse link and said switch being normally connected in series between said contacts, a combined fuse link extracting and indicating means biased towards outward motion and including a channel-shaped member normally straddling the lower portion of said fuse tube and restrained by said fuse link and having limited motion independently of said switch, and means for opening said switch when said combined fuse link extracting and indicating means moves outwardly.

10. A fuse construction comprisin a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said fuse link and said switch being normally connected in series between said contacts, a fuse link extracting member biased towards outward motion and normally restrained by said fuse link and having limited motionindependently of said switch, means operatively coupling said switch and fuse link extracting means to open said switch upon outward motion of said fuse link extracting means, and means engaged by said fuse link extracting means when said fuse link extracting means is moved back to its normal position for moving said switch towards its initial position.

11. A fuse construction comprising 2T housing having an open bottom and a door, a relatively stationary expulsion fuse tube mounted within said housing and having an open lower end adjacent the open bottom of said housing, a pair of contacts carried by said housing, a fuse link within said fuse tube, a switch within said housing, said fuse link and said switch being normally connected in series between said contacts, and combined signalling and fuse link extracting means normally within said housing adjacent the open bottom and biased towards motion outwardly through said open bottom and normally restrained by said fuse link, and means operatively connecting said switch and said combined fuse link extracting and indicating means to impart a positive opening motion to said switch from the outward motion of said combined fuse link extracting and indicating means upon rupture of said fuse link.

12. A fuse construction comprising a housing having an open bottom-and a door, a relatively stationary expulsion fuse tube mounted within said housing and having an open lower end adjacent the open bottom of said housing, a pair of contacts carried by said housing, a fuse link within said fuse tube, a switch within said housing, said fuse link and said switch being nor mally connected in series between said contacts, and combined signalling and fuse link extracting means normally within said housing adjacent the open bottom and biased towards motion outwardly through said open bottom andnormally restrained by said fuse link, and means operatively connecting said switch and said combined fuse link extracting and indicating means to impart a positive opening motion to said switch from the outward motion of said combined fuse linkextracting and indicating means upon rupture of said fuse link, said switch being located above said combined fuse link extracting and indicating means.

13. A fuse construction comprising a housing having an open bottom and a door, a relatively stationary expulsion fuse tube mounted within said housing and having an open lower end adjacent the open bottom of said housing, a pair of contacts carried by said housing, a fuse link within said fuse tube, a switch within said housing, said fuse link and said switch being normally connected in series between said contacts, and combined signalling and fuse link extracting means normally within said housing adjacent the open bottom and biased towards motion outwardly through said open bottom and normally restrained by said fuse link, and means operatively connecting said switch and said combined fuse link extracting and indicating means to impart a positive opening motion to said switch from the outward motion of said combined fuse link extracting and indicating means upon rupture'of said fuse link, said switch being located above said combined fuse link extracting and indicating means and said combined fuse link extracting and indicating means being located laterally of said fuse tube. V

14. A fuse construction comprising a housing having an open bottom, a fuse tube mounted within said housing, a pair of contacts within said housing, a fuse link within said fuse tube, a switch, said fuse link and switch being nor mally connected in series between said contacts, signalling means biased towards outward motion downwardly through the open bottom of saidMsing, said signalling means controlling the operatiorrofsaidsyvitch and being controlled by said fuse link, said signalling means and switch being pivotally mounted within said housing, and means operatively connecting said switch and signalling means at least during the final motion of said signalling means to cause said switch and signalling means to move as a unit to open said switch.

15. A fuse construction comprising a housing having an open bottom, a fuse tube mounted within said housing, a pair of contacts within said housing, a fuse link within said fuse tube, a switch, said fuse link and switch being normally connected in series between said contacts, signalling means biased towards outward motion downwardly through the open bottom of said housing, said signalling means controlling the operation of said switch and being controlled by said fuse link, said signalling means having fuse link extracting means, said signalling means and switch being pivotally mounted within said housing, and means operatively connecting said switch and signalling means at least during the final motion of said signalling means to cause said switch and signalling means to move as a unit to open said switch.

16. A fuse construction comprising a housing having an open bottom, a fuse tube mounted within said housing, a pair of contacts within said housing, a fuse link within said fuse tube,-

a switch, said fuse link and switch being normally connected in series between said contacts, and signalling means biased towards motion downwardly through the open bottom of said housing, said signalling means controlling the operation of said switch and being controlled by said fuse link, said signalling means andsaid switch being pivotally mounted within said housing and having means which engage each other at least during the final portion of the outward motion of said signalling means to cause said switch and signalling means to move as a unit to open said switch.

1'7. A fuse construction comprising a housing having an open bottom, a fuse tube mounted within said housing, a pair of contacts within said housing, a fuse link within said fuse tube, a switch, said fuse link and switch being normally connected in series between said contacts, and signalling means biased towards motion downwardly through the open bottom of said housing, said signalling means controlling the operation of said switch and being controlled by said fuse lnk, said signalling means having fuse link extracting means, said signalling means and said switch being pivotally mounted within said housing and having means which engage each other at least during the final portion of the outward motion of said signalling means to cause said switch and signalling means to move as a unit to open said switch.

18. A fuse construction comprising a housing having an open bottom, a fuse tube mounted within said housing, a pair of contacts within said housing, a fuse link within said fuse tube, a switch, said fuse link and switch being normally connected in series between said contacts, signalling means biased towards motion downwardly through the open bottom of said housing, said signalling means controlling the operation of said switch and being controlled by said fuse link, said signalling means and said switch being pivotally mounted within said housing and having means which engage each other at least during the final portion of the outward motion of said signalling means to cause said switch and signalling means to move as a unit to open said switch, and a spring normally urging said switch and signalling means towards rocking motion in opposite directions.

19. A fuseconstruction comprising a housing having an open bottom, a fuse tube mounted within said housing, a pair of contacts within said housing, a fuse link within said fuse tube, a switch, said fuse link and switch being normally connected in series between said contacts, signalling means biased towards motion downwardly through the open bottom of said housing, said signalling means controlling the operation of said switch and being controlled by said fuse link, said signalling means having fuse link extracting means, said signalling means and said switch being pivotally mounted within said housing and having means which engage each other at least during the final portion of the outward motion of said signalling means to cause said switch and signalling means to move as a unit to open said switch, and a spring normally urging said switch and signalling means towards rocking motion in opposite directions.

20. A fuse construction comprising a housing having an open bottom and an open front, a door for said open front, a fuse tube carried by said door and having an open end adjacent the open bottom of said housing, a pair of stationary contacts carried by saidhousing, a fuse link within said fuse tube projecting outwardly through the open end thereof, a switch, said switch and fuse link being connected in series between said stationary contacts, combined signalling means and fuse link extracting means biased towards motion through the open bottom of said housing and controlled by said fuse link, and means for mechanically interlocking said combined signalling and fuse link extracting means and said switch during at least the final portion of the outward movement of said combined signalling and fuse link extracting means.

21. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, sai'd switch and fuse link being normally connected in series between said contacts, and fuse link extracting means biased towards outward motion andhaving operative engagement with said switch for a portion only of the motion of said fuse link extracting means to open said switch when said fuse link extracting means moves outwardly, said fuse link extracting means having a portion normally engaging said fuse link, such portion being movable and in the initial portion of its motion withdrawing any remaining portion of said fuse link substantially in line with sad fuse tube.

22. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said switch andfuse link being normally connected in series between said contacts, and fuse link extracting means biased towards outward motion and having operative engagement with said switch for a portion only of the motion of said fuse link extracting means to open said switch when said fuse link extracting means moves outwardly, said switch when operatively engaged by said fuse link extracting means moving as a unit with said fuse link extracting means, said fuse link extracting means having a portion normally engaging said fuse link, such portion being movable and in the initial portion of its motion withdrawing any remaining portion of said fuse link substantially in line with said fuse tube.

23. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said fuse link and said switch being normally connected in series between said contacts, indicating means movable to indicating position upon rupture of said fuse link, and means for transmitting motion to said switch from said indicating means to open said switch when said indicating means has moved to indieating position, said switch electrically separating said indicating means from any live portion of said fuse construction after said switch has moved to open position.

24. A fuse construction comprising a pair of contacts, a fuse tube, a fuse link within said fuse tube, a switch, said fuse link and said switch being normally connected in series between said contacts, indicating means controlled by said fuse link and biased towards indicating position, and means for transmitting motion to said switch from said indicating means to open said switch when said indicating means has moved to indicating position, said switch electrically separating said indicating means from any live portion of said fuse construction after said switch has moved to open position.

25. A fuse construction comprising a housing having a pair of contacts, a fuse tube mounted within said housing, a fuse link within said fuse tube, a switch, said fuse link and said switch being normally connected in series between said contacts, indicating means normally housed within said housing and movable to indicating position with a part at least projecting from said housing upon rupture of said fuse link, and means for transmitting motion to said switch from said indicating means to open said switch when said indicating means has moved to indieating position, said switch electrically separating said indicating means from connection with any live portion of said fuse construction when said switch has moved to open position.

26. A fuse-construction comprising a housing having an open bottom, a fuse tube mounted within said housing, a pair of contacts within said housing, afuse link withinsaid fuse tube, a switch, said f'u's'e link and said switch being nornially connected in series between said contacts, and signalling means biased towards motion downwardly through the open bottom of said housing, said signalling means controlling the operation of said switch and being controlled by said fuse link, said signalling means and said switch being mounted within said housing and having means which engage each other at least during the final portion of the outward motion of said signalling means to cause said signalling means and switch to move as a unit to open said Switch, said'switch electrically separating said signal-ling means from any live portion of said fuse construct-ion when said switch has moved to open position.

27'. In a fuse switch, spaced terminals, means supporting a fuse tube in series circuit relation with said terminals, a fuse link extracting memher and a terminal engaging contact member pivotally mounted on said fuse tube for rotation about a common axis; a fuse link within said fuse tube connected in series with said terminal engaging contact member between said spaced terminals, and resilient means urging said fuse link extracting member in a direction to tension said fuse link, saidterminal engaging contact member having a portion thereof positioned in. the-path of movement of said fuse --1ink extracting member, the arrangement being such that said terminal engaging contact member is struck a blow following a predetermined movement of said fuse link extracting member which occurs without movement of said terminal engaging contact member to thereby disengage said terminal engaging contact member upon rupture of said fuse r link.

28. In afuse switch, spaced terminals, a fuse tube, a swingably movablefu'se link extracting member at the lower endof said tube, a swing ably movable contact member positioned in the path of movement of said fuse link extracting member and arranged to be engaged by the latter after its movement for a predetermined distance along said path while said contact member remains unmoved, resilient means urging said fuse link extractingmember ina direction to'engage said contact member, and means including a fuse link extending through said fuse tube electrically connecting.said terminals, said fuse link restraining said fuse link extracting mjember while said fuse link remains un'ruptured' and releasing said fuse link extracting member when said fuse link is ruptured.

29. In a fuse jswitch, spaced terminals, 'a fuse tube, a swing'ably movable fuse link extracting member and a 'swinga'bly movable contact member 'pivotally mounted/at the lower end of. said fuse tube forrotation about. a common axis, said contact member having a portion thereof interposed in the path of movement of said fuse link extracting member, resilient means urging said fuse link extracting member in a direction to strike and initiate movement of said contact member only after said fuse link extracting member has move'dfa predetermined distance, and means including a ruse link extending through said fuse tube electrically connecting said terminals, said fuse link normally restraining said fuse link extracting member and releasing said fuse link extracting member'when said fuse link is ruptured.

30. A fuse switch comprising an insulator, spaced terminals supported thereon, a fixed fuse tube mounted on said insulator, a swingably movable fuse link extracting member and a swingably movable terminal engaging contact pivotally mounted on said fuse tube at the lower end thereof for rotation about a common axis, said contact normally engaging one terminal of the said terminals and having a portion thereof interposed in the path of movement of said fuse link extracting member, resilient means urging said fuse link extracting member so as to strike and initiate movement of said contact in a direction to disengage the latter from said one terminal only after said fuse link extracting member has moved a predetermined distance, and means including a fuse link extending through said fuse tube electrically connecting said terminals, said fuse link normally restraining said fuse link extracting member and releasing said fuse link extracting member upon rupture of said fuse link.

31. In a circuit interrupter, a terminal member, a contact member movable to and away from said terminal member to respectively close and open the circuit, a spring pressed movable fuse link extracting member arranged to strike said contact member following unimpeded movement of said fuse link extracting member over a predetermined path sufficiently long to impart theretos ubstantial momentum, said movement occurring while saidhcontact member remains unmoved, and a fuse link serially connected in said circuit and normally restraining said fuse link extracting member and releasing said fuse link extracting member when said fuse link is ruptured.

32. In a fuse switch, a fuse tube, a supporting member rigidly secured to said tube, a terminal, a contact member arranged for movement between an engaged and a disengaged position with respect to said terminal, a fuse link extracting member pivotally supported from said fuse tube and so constructed and arranged as to impact and thereby actuate said contact member from the engaged to the disengaged position following a predetermined movement of said fuse link extracting member, said contact member remaining unmoved while said predetermined movement occurs and moving only after being impacted by said fuse link extracting member, biasing means urging said fuse link extracting member towards extracting motion, and a fuse link normally restraining said fuse link extracting member.

33. In a fuse switch, spaced terminals, a fuse tube supported in series circuit relation with said terminals, a fuse link extracting member and a terminal engaging contact member pivotally mounted on said fuse tube for rotation about a common axis, a fuse link within said fuse tube having its ends respectively electrically connected to one of said terminals and to said terminal engaging contact member, said fuse link extracting member normally extending across said fuse tube when said fuse link is unfused, and means responsive to the rupture of said fuse link for actuating said terminal engaging contact memher to the disengaged position following a predetermined movement of said fuse link extracting member, the said predetermined movement rotating said fuse link extracting member so that a portion thereof swings outwardly away from the fuse tube to an indicating position.

34. In a fuse switch, spaced terminals, a fuse tube supported in series circuit relation with said terminals, said fuse tube having mounted thereon for limited rotation about a common axis and in the same direction a fuse link extracting member and a terminal engaging contact member, said fuse link extracting member normally extending laterally across said fuse tube, a fuse link Within said fuse tube normally electrically connecting said terminals, said fuse link having its ends electrically connected respectively to one of said terminals and to said terminal engaging contact member, resilient means biasing said fuse link extracting member for rotation in a direction to tension said fuse link, and means responsive to a predetermined movement of said fuse link extracting member under the influence of said resilient means following the rupture of said fuse link for actuating said contact engaging member to the disengaged position, the said predetermined movement rotating said fuse link extracting member so that a part thereof moves outwardly away from said fuse tube to an indicating position.

WILLIAM O. SCHULTZ. 

